Columbia Grammar School was founded in 1764, just 10 years after the founding of Kings College, which became Columbia College, now part of Columbia University. Originally established as a boys preparatory school for Kings College, Columbia Grammar School functioned for 100 years under the direct auspices of the college.

One of the most illustrious headmasters during that period was Dr. Charles Anthon, a distinguished classical scholar. During his tenure, Columbia Grammar School provided more than half the students to Columbia College'sclass. In 1864, when Dr. Anthon retired as headmaster, the trustees of Columbia College terminated their relationship with Columbia Grammar School, and the school became a proprietary institution, only achieving its non-profit status in 1941. 

In 1937, the Leonard School for Girls was founded, using several interconnected brownstones on West 94th Street. In 1956, the Leonard School joined with Columbia Grammar School to become a co-educational institution. Today the row of 94th Street brownstones house students in Pre-Kindergarten through Grade 2. The school's name was officially changed to Columbia Grammar and Preparatory School in 1978. 

As only the 13th headmaster in the Columbia Grammar and Prep's long history, Dr. Richard J. Soghoian was appointed in 1981. Over the past three decades, he has expertly guided the physical expansion of the school from its 1904 home at 5 West 93rd Street to the present complex, which also includes two high school buildings and additional brownstones on West 94th Street and educates 1,300 students, Pre-K-Grade 12. In 2014, Columbia Grammar and Preparatory School will celebrate its 250th anniversary as one of the oldest independent schools in the United States.